Abstract
Introduction
Navigation system has been used for very accurate surgery. It can also be useful for preoperative planning. A surgeon can understand whole surgery, plan the surgery and perform the surgery three dimensionally and accurately. But the planning procedures should be installed before everything is started. When the surgery will be done in an ordinary method, the surgeon would not find particular difficulties. But in sometimes the surgeon can have unordinary situation such as massive defect that should be treated with acetabular enforcement device and bone grafted. Using postoperative DICOM data which is predicted by preoperative planning using 3D CAD software, we will be able to use the navigation system for those cases with difficulties that is not supported.
Objectives
To establish a method to use a navigation system using preoperative planning data that is processed by our 3D CAD software which is not supported by the navigation system itself, including device preparation using plastic models.
Materials and Methods
CAT scan data performed before hip arthroplasty with acetabular enforcement plate were used. Data conversion was done by Mimics® then preoperative planning was done by Magics® (Materialize, Belgium). Plastic bone models were machined by Modella MD-40 (Roland DG, Japan). The acetabular plate was bent to fit to the plastic model. Then the plate was CAT scanned on the plastic model because the geometry is no longer same with original. This CAT scan data and original data were combined and processed and exported as a set of DICOM data. At the surgery, the DICOM data was input. After registration, the planned acetabular plate which was not actually exit could be seen on the screen. CAT scan was done after surgery and the difference from the plan was evaluated.
Results
On navigation screen, the postoperative geometry was displayed. Moving prove, the detail could be observed (Fig. 1). The difference between preoperative plan and postoperative alignment was very close (Fig. 2).
